Installation for pulverizing and drying crude quarry products

ABSTRACT

A pulverizing and drying installation in which hot gas is supplied in parallel to a breaking machine, a separator and a crusher, the gases from the breaking machine and the crusher being sent to the separator whence a single gas flow charged with pulverulent material is sent to a filter.

United States Patent INSTALLATION FOR PULVERISING AND DRYING CRUDE QUARRY PRODUCTS 3 Claims, 2 Drawing Figs.

U.S. CI 241/42 Int. Cl B02c 21/00 Field of Search 241/42- [56] References Cited UNITED STATES PATENTS l,729,424 9/1929 Harshaw 241/42 1,748,920 2/1930 Newhouse 241/43X 2,274,789 3/1942 I-Ioresi 241/42X 3,329,353 7/1967 Knudsen. 241/43 3,397, 45 3 1968 Mueller 241/43 Primary Examiner Donald G. Kelly Attorney-Cameron, Kerkam and Sutton ABSTRACT: A pulverizing and drying installation in which hot gas is supplied in parallel to a breaking machine, a separator and a crusher, the gases from the breaking machine and the crusher being sent to the separator whence a single gas flow charged with pulverulent material is sent to a filter.

e l 10 i I i I 30/ I,

i l r 26 f I V 4 ENS'HALLATHON FOR PULVERISING AND DRYING CRUDE QUARRY PRODUCTS The invention relates to an installation for pulverizing and drying crude quarry products, using the hot gases coming from a furnace for treating pulverulent materials, more particularly an installation for crushing materials for cement manufacture; the outlet gases from the treatment furnace can also have been used for the preheating of the raw materials before their introduction into the furnace.

Crushing installations are known which mainly comprise a breaking machine, for instance of the impact type, a dynamic separator, and a crusher, for instance of the ball-and-drum type, the materials passing successively into the breaking machine and the crusher, if necessary with recycling of inadequately crushed materials.

In installations of the kind specified, hot gas flows coming from a single hearth, or from hearths associated with each apparatus, flow through the apparatuses. From each apparatus therefore a gas flow escapes which entrains pulverulent materials, and the flows are received separately or regrouped in static separators from which the materials are extracted. Another portion of the materials is extracted from the base of the outer casing of the dynamic separator.

in an installation of the kind specified it is very difficult to equilibrate the gas flows passing through the various apparatuses, so that the pulverulent materials which they entrain have the same grain size and the same hygrometric degree in all apparatuses.

The invention obviates these disadvantages by sending a hot gas flow in parallel to the breaking machine, the dynamic separator, and the crusher, the gases emerging from the breaking machine and the crusher being then sent to the dynamic separator, whence a single gas flow charged with pulverulent materials is sent to the equipment for filtering and separating the materials.

An exemplary embodiment of the invention will now be described in greater detail, with reference to the drawings, wherein:

FIG. 1 illustrates diagrammatically the operation of a complete installation for crushing raw materials for cement manufacture; and

H0. 2 is a detail of the construction of the dynamic se arator.

Referring to FIG. I, raw material having an approximate grain size of --25 mm. or more is taken from a storage silo 1 by a distributor 2 and introduced into a hammer-type breaking machine 3. The broken up materials, except for the portion already in the pulverulent state, are collected in an air lock 4 in the lower portion of the apparatus and sent from there to the base of an elevator 5. In the upper portion of the elevator 5, the materials are poured out onto a screen 6 whose meshes allow elements having a grain size of 0-6 mm. to pass through, the refuse being collected at a place 7 and returned to the inlet of the breaking machine 3.

The fraction of the material which passes through the screen 6 is sent by a conveyor 8 to a dynamic separator 9. The materials introduced into the dynamic separator are received on a centrifugal rotary plate 10 driven by a motor 11. The heavy fractions collected at the baseof the dynamic separator in an air lock 12 are introduced into a single-chamber balltype crusher 13. The materials leaving the crusher are collected in air lock 14, whence they are sent to the base of the elevator 5, where they are mixed with the materials coming from the breaking machine. The hot gas flow coming from the treatment furnace or the preheater is entrained by a general fan l5 and, if necessary, extra heating is provided by a hearth 16.

Some of the gas flow is sent through ducting 17 to the impact-type breaking machine 3, through which it passes in counter current, entraining into outlet ducting 18 the finer portions of the material treated. Another portion of the gas flow is sent via ducting 19 to the ball-type crusher 13, whence it emerges at a place 20, entraining the finer portions of the material crushed. The majority of the hot gas flow is sent at a place 21 to the lower portion of the drying column of the dynamic separator 9. The dynamic separator 9 also receives at a place 22 the gas'flows which have passed through the braking machine and the crusher. The fine materials separated by the separator 9 are entrained by the gas flow emerging at a place 23 and successively sent into a decanting tower 24 and an electric filter 25, whence they are extracted and evacuated on a conveyor 26. Registers 27, 28 enable the relative amount of the gas flow to be regulated as between the breaking machine, the crusher and the dynamic separator. Downstream of the fan 29, a conduit 30 having a register 3] enables the gas flow emerging from the electric filter to be recycled to the dynamic separator, while the rest of the gas flow is evacuated at a place 32 to the chimney. A conduit 33 enables the gases coming from the fan 15 to pass directly to the filtering and separating group 24, 25 without passing through the crushing apparatuses when the latter are not in operation.

The installation is completed by a thermal regulating device which samples the temperature of the mixture of gases and pulverulent materials in the outlet ducting 23 for the gases from the dynamic separator, the device acting either on the auxiliary hearth or on the water atomization at the inlet to the breaking machine-3 or the decanting tower 24.

Referring to FIG. 2, the dynamic separator is formed by a cylindrical member 40 through whose cover central feed ducting 41 extends. A rotor 42 is suspended from the inside of the member 40 by a drive shaft 43 which extends through the central ducting and is connected to a drive motor 44. The rotor R comprises a plate 45 and a portion 46 forming a centrifugal turbine. A frustoconical element 47 defines at the base of the member 40 an annular compartment 48 in which gases fed via nozzles 49 are distributed; the gases then pass into the actual separator via an annular space 50.

The cylindrical member 40 is continued at its base by a conical portion 51, and then a cylindrical drying column 52 which terminates at its base in an evacuating pipe 53. A lateral gas inlet 54 discharges into the column 52 via a grid 55 whose inclined blades form a screen to the passage of the solid materials into the conduit 54.

The solid materials of varying grain size are introduced into the ducting 41 from which they drop on to the rotary plate, which distributes them in the gases by centrifugal effect. A first sizing is performed by gravity, while the turbine 46 performs a second centrifugal selection by hurling the heavier materials against the walls. The materials encounter in the separator the gas flow distributed by the compartment 48 and the gas flow coming from the ducting 54. These two currents entrain the pulverulent materials upwards, while the dense materials drop back into the ducting 53, after having lost some of their humidity in contact with the hot flow. All the gas flows and the whole of the pulverulent materials in suspension are evacuated via a nozzle 56.

In the resulting crushing installation, the dynamic separator is of a simpler construction than in the prior art types; more particularly, the separator has neither the prior art external separating chamber, nor the prior art-internal circulation turbine. The result is that the useful section of the separator is increased, thus allowing the passage of a considerable gas flow capable of entraining all the fine materials to the filtering and separating group. The whole installation has the advantage of a large section for the passage of the gases, and therefore a small load loss.

The amount of gas flow in the lower column of the separator, and its mixing, after contact with the material, with the gas flow distributed by the compartment 40, also improves the drying of the dense products, thus giving improved yield from the crusher receiving these products.

Equilibrium of operation of the dynamic separator is ensured with constant flow, even if the general flow of the installation should vary, as a result of the recycling circuit initiated by the conduit 30 downstream of the filtering and separating group.

The installation described hereinbefore and embodied according to the invention enables the temperature regulation of the gases and materials to be simplified as a result of the regrouping of all the pulverulent materials in suspension in a single gas flow at the outlet from the dynamic separator.

The installation thus designed can also operate with variable flow, following the variations in flow of the furnace for treating the materials, If the flow is reduced, for instance, in relation to the nominal fiow of the installation, the breaking machine can be slightly opened while maintaining the same aperture in the grid of the screen 6, thus increasing the amount of materials recycled at the place 7. The flow of the dynamic separator can also be kept constant by recycling via ducting 30. To avoid excessive crushing in the crusher 13, the latter can have a motor whose speed can be slightly varied, so that the crusher can be operated at reduced speed, in relation to the reduced flow of the installation.

Of course, the foregoing description is merely exemplary, and the scope of the invention would not be exceeded by an installation differing slightly therefrom, for instance, by modifications to the details of the construction of the dynamic separator. Similarly, the breaking or crushing apparatuses can be of some other type than those described hereinbefore.

Lastly, the raw materials coming from the silo could alternatively be introduced into the installation only at the base of the elevator, after the breaking machine, in which case the fine portions of the raw material would be immediately separated by the screen and sent to the separator, while only the refuse would be sent to the breaking machine for the first crushing.

lclaim:

1. An installation for pulverizing and drying crude quarried products utilizing the hot gases from a treatment furnace for the pulverized materials comprising a crusher, an upper inlet for the introduction of crude products into said crusher, a lower outlet in said crusher for crushed materials, a lower inlet in said crusher for the introduction of hot gases, an upper outlet in said crusher for removal of gases, a screen, a tube mill, an entry in said tube mill for crushed materials, an outlet from said tube mill for crushed materials, an inlet in said tube mill for hot gases, an outlet from said tube mill for gases, a dynamic separator, a lower chamber for said separator for the discharge of coarse crushed materials, a lower inlet in said separator for hot gases opening into said lower chamber, an intermediate inlet in said separator for hot gases, an upper inlet in said separator for crushed materials, an upper outlet in said separator for gases and crushed materials, separate conduits for feeding hot gases to said crusher, to said tube mill,

and to said separator, means for supplying to said screen the crushed materials leaving said crusher, means for returning to said upper inlet of said crusher the crushed materials not passing through said screen, means for supplying to the upper inlet of said separator the crushed materials passing through said screen, means for supplying to the inlet of said tube mill the crushed materials from said lower chamber of said separator, means for supplying to said screen the crushed materials leaving said tube mill, means for supplying the gases leaving said tube mill and said crusher to said intermediate inlet of said separator and means for conducting the gases from said upper outlet of said separator to a device for filtering and separating the crushed materials from the gases.

2. An installation as set forth in claim 1, said dynamic separator comprising an external casing formed by an upper cylindrical portion, a lower cylindrical column portion of lesser diameter, said two portions being interconnected by an intermediate conical portion, a rotary plate forming a centrifuge and disposed in said upper cylindrical portion of said casing, a motor for driving said rotary plate, a device for introducing the materials on to said rotary plate, at least one gas inlet disposed in said conical portion of said casing, a gas inlet so disposed in said lower cylindrical column portion as to direct the gas flow upwards, and an air lock for evacuating the granular materials in the lower portion of said separator.

3. An installation as described in claim 1, said means for supplying to said screen the crushed materials leaving said crusher and said means for supplying to said screen the crushed materials leaving said tube mill including a common elevator means discharging onto said screen. 

1. An installation for pulverizing and drying crude quarried products utilizing the hot gases from a treatment furnace for the pulverized materials comprising a crusher, an upper inlet for the introduction of crude products into said crusher, a lower outlet in said crusher for crushed materials, a lower inlet in said crusher for the introduction of hot gases, an upper outlet in said crusher for removal of gases, a screen, a tube mill, an entry in said tube mill for crushed materials, an outlet from said tube mill for crushed materials, an inlet in said tube mill for hot gases, an outlet from said tube mill for gases, a dynamic separator, a lower chamber for said separator for the discharge of coarse crushed materials, a lower inlet in said separator for hot gases opening into said lower chamber, an intermediate inlet in said separator for hot gases, an upper inlet in said separator for crushed materials, an upper outlet in said separator for gases and crushed materials, separate conduits for feeding hot gases to said crusher, to said tube mill, and to said separator, means for supplying to said screen the crushed materialS leaving said crusher, means for returning to said upper inlet of said crusher the crushed materials not passing through said screen, means for supplying to the upper inlet of said separator the crushed materials passing through said screen, means for supplying to the inlet of said tube mill the crushed materials from said lower chamber of said separator, means for supplying to said screen the crushed materials leaving said tube mill, means for supplying the gases leaving said tube mill and said crusher to said intermediate inlet of said separator and means for conducting the gases from said upper outlet of said separator to a device for filtering and separating the crushed materials from the gases.
 2. An installation as set forth in claim 1, said dynamic separator comprising an external casing formed by an upper cylindrical portion, a lower cylindrical column portion of lesser diameter, said two portions being interconnected by an intermediate conical portion, a rotary plate forming a centrifuge and disposed in said upper cylindrical portion of said casing, a motor for driving said rotary plate, a device for introducing the materials on to said rotary plate, at least one gas inlet disposed in said conical portion of said casing, a gas inlet so disposed in said lower cylindrical column portion as to direct the gas flow upwards, and an air lock for evacuating the granular materials in the lower portion of said separator.
 3. An installation as described in claim 1, said means for supplying to said screen the crushed materials leaving said crusher and said means for supplying to said screen the crushed materials leaving said tube mill including a common elevator means discharging onto said screen. 